This research will study the effects of maternal depression, psychosocial stress, and psychotropic medication on fetal/infant neurobehavioral development. Participants will include pregnant women diagnosed with: major depressive disorder who are prescribed antidepressant medications (i.e., SSRIs) (n = 40); major depressive disorder who are not prescribed SSRIs (n = 40), and a control group of pregnant women without a psychiatric diagnosis (n = 80) who are matched to the depressed groups on race, age, and SES. Actocardiographic technology will assess fetal behavioral and heart rate response to mild vibratory stimulation at 26-28 weeks gestation and again, between 32-34 weeks gestation. At each visit maternal psychiatric/stress symptoms will be measured with the Beck Depression and Anxiety Inventories, the Schedule of Recent Life Events and the Perceived Stress Scale. Maternal coping skills will be measured with the Coping Responses Inventory. Maternal urine samples will be assayed for prescribed medication and/or illicit drugs. Maternal saliva will be assayed for cortisol. Medical ultrasound records will be examined for physical length, head circumference and presence of abnormalities. During labour, fetal heart rate will be monitored and umbilical cord blood will be assayed for cortisol. On the first postnatal day, a behavioral observation will be obtained from neonates, they will be administered the BNBAS, salivary cortisol samples will be gathered and obstetrical/postnatal complications documented. In addition, another psychometric assessment will be made of each mother and saliva and urine samples obtained. A one-month follow-up will consist of another behavioral observation of the infant, re-administration of the BNBAS, obtaining mother/infant salivary cortisol samples, as well as a final maternal psychometric assessment and urine sample. Parametric statistical analyses and regression modeling will examine the relationships between maternal psychiatric symptoms, antidepressant medication, psychosocial stress and maternal coping, fetal and postpartum behavior and maternal/fetal/infant cortisol. It is predicted that fetal/infant physiological, behavioral, and hormonal patterns will vary with maternal diagnosis, degree of psychosocial stress and maternal coping strategy, and medication status and that with the amelioration of depressive symptoms via SSRIs, fetal/infant developmental profiles among the depressed women will more closely approximate those of the non-depressed control group.